2 inch parfocal stop ring

This is a small add-on I designed to use with my new 2 inch astronomy camera. The stop ring can be put over a 2" barrel and be locked using the M3 thumbscrew to define a precise stop at a defined distance.
Useful if you change cameras often and you want to make sure they have the same point of focus, i.e. they are parfocal.

The ring actually consists of 2 parts but they are printed together. There is a small inset that is pushed by the m3 thumbscrew towards the 2" barrel so the screw doesn't touch the barrel directly, preventing scratches and evenly distributing the pressure.

The M3 gear in the ring should be strong enough to hold the ring on the barrel - if you want or need higher precision or want it to be more sturdy and durable, you also could use a M3 heat set insert (e.g. M3x5.7x4.6).

For printing I used ABS with 30% infill.